Boat construction



- |NvENToR Q 0H/v H, SMEDMY Y Oct. 4, 1932.

J. H. SMEDLEY 1,880,366

BOAT CONSTRUCT ION Filed Dec. 1'7, 1931 2 Sheets-Sham.v l

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BY ATTORN EYS WMM OC. 4, 1932. j` H SMEDLEY 1,880,366

BOAT CONSTRUCTION Filed Dec. `1'7, 1931 2 Sheets-Sheet 2 INVENTOR JaH/y H. sMfDLfY /4 BY ATTORNEYS isf Patented oct. 4, 1932 QNITED STATES PATENT OFFICE BOAT CONSTRUCTION Application filed December 17, 1981. Serial No. 581,551.

This invention relates to power boats and more particularly to power boats adapted to attain moderate and high speeds.

It is one of the principal purposes in all power boat designs to diminish the resistance to the movement of the boat through the water and thereby attain a maximum of speed with a minimum expenditure of power. The principal factors which impede the movement of a boat through the water are the resistance to displacement of the water in the path through which the boat moves, and the skin friction of the wetted surface of the boat. In order to reduce both these factors, boats have been so designed that at moderate or high speeds the bow is lifted by the reaction of the water on the bottom of the boat. Among the prior constructions heretofore produced have been the sea sled, the monostep flat bottom boat and the monostep V- bottom boat. In all of these constructions, however, the stern of the boat is depressed to a point below that at which it lies when the boat is at rest or is driven at a relatively low speed. Although the lifting of the bow reduces the water displacement and the wetted area, the depressing of the stern is a great y disadvantage. v

The principal object of the present invention is to improve the design of power boats with a view of enabling such a boat to be driven with a given expenditure of power at a higher speed than can be attained with the constructions heretofore produced.

Another more specific object of the present invention is to design a power boat in which, as the boat increases in speed, both the bow and the stern will beY lifted by the reaction of the water on the boat bottom.

With these objects in view a feature of the present invention consists in the provision in a power boat construction of a bottom having a` bulge constructed and located to lift the stern of the boat as the speed of the boat increases. This bulge is preferably located somewhat aft of the center of gravity of the boat. A relatively slight bulge in the boat bottom in this location will result in lifting the stern of the boat as the boat increases in speed, and the lifting of both bow and stern will enable the boat to plane upon surfaces comprising the forward part of the hull and the forward part of the bulge.

The invention will be clearly understood from the accompanying drawings illustrat- -ing a construction embodying the invention in its preferred form, and the following detailed description of the construction therein shown.

In the drawings Figure 1 is a view in side elevation illustrating a boat construction embodying the invention;

Figure 2 is an underside plan view of the boat;

Figure 3 is a view in side elevation on an enlarged scale of a portion of the bottom of the boat;

Figure 4 is a diagrammatic view illustrating the transverse outlines of a hull having one type of bottom embodying the invention at different points in the length of the hull.

Figure 5 is a diagrammatic view similar to Figure 4 illustrating the corresponding transverse outlines of a hull having a different type of bottom embodying the invention;

Figure 6 is a view in side elevation illustrating a hydroaeroplane having a fuselage embodying the invention;

Figure 7 is an underside plan View of the fuselage of a hydroaeroplane illustrated in Fig. 6; and

Figure 8 is a View in front elevation of said fuselage.

The invention is shown in the drawings as embodied in a boat having a pointed bow, a square stern, and having the sides meeting the bottom at angles defining the chine lines. ln the construction shown in Figs. l, 2 and 3 of the drawings, the boat comprises a b0t tom indicated at 2, sides indicated at 4 meet-s ing the bottom at the chines indicated at 6, and a keel indicated at 8. y

The invention may be 'rembodied in boats of varying shapes, and relates particularl to the construction of a boat bottom. Fre erably the invention is embodied in a boat of the type having a il-bottom bow portion, and a round bottom or circle bottom amidships and from amidships to the stern. Figure 4 illustrates diagrammatically the transverse outlines of the hull of a boat of this type at different points in the length of the hull. The lines a-a to g-g in this figure indicate transverse outlines of the hull in planes substantially perpendicular to the longitudinal axis of the boat taken respectively on the lines A to G inclusive in Figure 1. The lines a to g in Figure 4 indicate respectively the transverse outlines of the boat bottom in the respective planes. The lines a and b', indicating the transverse bottom outlines of the bottom portion of the boat in the planes taken on the lines A and B of Figure 1, are substantially straight. The lines c to g, Figure 4, indicating the transverse bottom outlines in the lplanes taken along the lines C to G in Figure 1 are the arcs of circles.

It will be noted from an inspection of Fig. 4 that thebottom from the bow of the boat to the plane taken on the line C, Figure 1, is inclined to a considerable degree downward ly as well as being inclined to the central plane of the boat. The result of this construction of the bow is that the bow will be lifted by the reaction of the water on the same when the boat is driven at moderate or high speeds.

In order to lift the stern of the boat when lit is driven at moderate or high speeds, the bottom of the boat is provided with a bul e indicated at 10. This bulge is preferab y located aft of the center of gravit of the boat, and its location usually is a t of the center of the boat. As shown in Figure 1, the bulge starts at about the plane taken on the line F. Its high point occurs at about the plane taken on the line E. When applied to a round bottom, or circle bottom boat, the transverse outline of the bulge in any plane perpendicular to the axis of the boat and intersecting the bulge preferably consists of the arc of a circle. The leading edge portion and also the trailing edge portion of the bulge preferably blend smoothly into the portions of the bottom respectively forward and aft of the bulge. The line d', in Figure 4, indicates the shape of the bottom at the beginning of the bulge, and the line e and f indicate the shape of the bottom respectively at the high point and at the termination of the bulge. The bulge itself has an outwardlycurved outline longitudinally of the boat, and forms in connection with the portion of the bow immediately forward of the bulge a reentrant curve in the bottom, the center of which is located at about the plane taken on the line D of Figure 1.

With the above construction the bulge 10 has practically no eect when the boat is driven at relatively low speeds. When the boat reaches a speed of about 15 to 20 miles per hour, the bow of the boat starts to rise. This increases the angle of the forward portion of the bulge to the surface of the water or to the direction of movement of the boat, A

and this increases the lifting reaction of the water on the stern portion of the boat. As the boat is driven at still higher'speeds, the bow is depressed slightly and the stern is lifted by the reaction of the water on the bulge. T'he construction is preferably such that when the boat is driven at a relatively high speed, the bow and the stern are both lifted suiiciently to bring the chines near to, or above, the surface of the water.

As shown in Figure l, the dot-and-dash lines W.L. indicate the water line when the boat is at rest on the surface of the water, and the line WL indicates generally the wate` line when the boat is drivenat high spee .A

Figure 5 illustrates diagrammatically the shape of the hull of a boat of the V-bottom type having the invention embodied therein. This figure shows the transverse outlines of the hull in planes perpendicular to the axis of the hull taken'along lines corresponding to the lines A to G inclusive of Figure 1. The lines a2 to g2 inclusive in Figure 5 indicate the shape of the sides of the hull, and the lines a3 to g3 inclusive indicate theshape of the bottom.

Figures 6, 7 and 8 illustrate a hydroplane having a fuselage 12 embodying the present invention. The bow portion of the fuselage is so constructed that when the fuselage is driven at moderate or high speeds on the surface of the water, the reaction of the water will lift the bow. In order to lift the stern portion of the fuselage, the bottom of the same indicated at 14, is provided with a bulge 16. This bulge is preferably located aft of the center of gravity of the fuselage and the reaction of the water on the same when the plane is driven on the surface of the water at moderate or high speeds will lift the stern portion of the fuselage.

It is to be understood that the invention is not limited to the particular construction or arrangement of parts of the illustrated embodiment of the invention, but that the invention may be embodied in other forms within the scope of the claims.

Having explained the nature and object of the invention, and having specifically described a construction embodying the invention in its preferred form, what is claimed 1s 1. A boat having a bottom formed without a bulge forward of the center of gravity, and having a bulge aft of the center of gravity, the leading and trailing surfaces of which blend with the adjacent surfaces of the bottom of the boat.

2. A boat having a bottom formed with a bulge located aft of the center of gravity of the boat and diminishing in depth from the keel outwardly toward the sides of the boat, the surfaces of the bulge blending smoothly with the adjacent surfaces of the boat bottom.

3. A boat having a bottom formed with a bulge having a rounded outline longitudinally of the boat and extending slightly outwardly from the normal line of the bottom aft of the center of gravity and extending across the greater part of the width of the boat and diminishing in depth from the keel outwardly towards the sides of the boat, the outer surface of said bulge forming a continuation of the outer surfaces of the bottom forward and aft of the bulge.

4. A boat having a bottom formed to a smooth outline longitudinally from the bow to the stern fore and aft, and having a single bulge in said bottom and located aft of the center of gravity and at a substantial distance from the rear end, and blending smoothly into the adjacent portions of the bottom.

Signed at New York, N. Y., this 14th day of December 1931.

` JOHN H. SMEDLEY. 

